In the medical field, it is often desirable to utilize a drug infusion catheter to deliver several IV fluids to a patient at one time. The fluids may include a parenteral fluid and one or more medications. In such a case, a drug infusion catheter with two or more delivery lumens may be used. A typical drug infusion catheter is shown in FIG. 1.
When a drug infusion catheter is used, it is often left in the patient's vascular system for extended periods of time, sometimes as long as 48 hours. In order to secure the catheter in place, the physician often sutures the catheter to the patient at or near the insertion site. This prevents the catheter from pulling out or advancing further into the patient's vascular system. This in turn prevents contamination of the patient, which can occur if the catheter portion that has been outside the body and exposed to the environment slips into the patient's vessel.
In addition to drug infusion catheters, other types of catheters for other medical applications may also need to be sutured to the patient at or near the insertion site.
As shown in FIG. 1, suture loops are generally provided on the backform 13 of a catheter, that is, the connector between the catheter 15 and the extension tubes 17 which communicate with the lumens in the catheter. Typically, the backform 13 is injection molded with a suture loop 11 on either side as shown in FIG. 1. Thus, the suture loops 11 are integral with the backform 13 of the drug infusion catheter 15.
The disadvantage of this type of suture loop is that if the catheter is not inserted completely into the patient's vascular system, the suture loops 11 may be positioned too distant from the insertion site to provide proper catheter anchoring. Attempts to solve this problem have resulted in a suture loop permanently positioned along the catheter tube slightly distal of the backform as shown in FIG. 2.
The suture loop 19 is typically a separate injection-molded part formed of polyvinyl chloride that is adhesively-bonded directly to the catheter 15 at the desired location during manufacture. This practice limits the suture loop's utility to those cases where the catheter is inserted to some predetermined depth. Unless the catheter is advanced to the predetermined depth, the suture loop will not be positioned at the desired location for properly anchoring the catheter. Adhesively-bonding the suture loop to the catheter has the additional disadvantage of creating a stress-concentration and reducing the load-carrying capability of the catheter body tubing. This type of suture loop also has an added cost of the labor involved in permanently attaching the suture loop to the catheter during manufacture.
Attempts have been made to create a suture loop that can be positioned anywhere along the length of the catheter, such as the suture loop 21 shown in FIG. 3. This type of suture loop is injection-molded with suture loop holes 22 and a pre-formed slot 23 which permits the suture loop to be slipped onto a catheter at any position along the length of the catheter tubing. The suture loop is typically formed of a pliable elastomeric material so that the slot can be opened to receive the catheter but yet is resilient enough to partially close onto the catheter.
Other suture loops have been provided similar to that shown in FIG. 3 but without the pre-formed slot so that the suture loop is slid onto the catheter over the catheter tip and slid to the desired location along the length of the catheter tubing prior to insertion of the catheter into the patient. The disadvantage of these two suture loops is that fluids from the patient's body, medical cleansing agents, medications and/or other liquids the patient might be treated with tend to wet the surface of the catheter, causing fluid to enter the channel 25 formed within the suture loop. This can cause the suture loop to slip along the catheter tubing resulting in unstable anchorage of the catheter.